JPH083455B2 - Switch with failure prediction function - Google Patents

Description

TECHNICAL FIELD OF THE INVENTION The present invention relates to a switch capable of knowing a failure state in advance.

[Prior art and its problems]

Conventionally, there are a plunger type limit switch having a snap-action switch built into the housing and having an operating plunger protruding to the outside of the housing, and a roller lever type limit switch for converting the rotational movement of the roller lever into a linear movement.

However, in these switches, cutting oil adheres between the operation plunger and the head, or between the rotary shaft supporting the roller lever and the head, and the cutting oil solidifies or the cutting powder adheres to the operation plunger or the cutting oil. There is a possibility that the roller lever and the movable portion including them may cause a return failure, overtravel, that is, insufficient movement after the operation, or in the roller lever type, an operation failure or a setting failure due to wear of the roller.

On the other hand, the built-in switch may cause contact failure due to welding of contacts or dust adhering to the contacts, or breakage of the movable contact plate, which may cause product failure in the mechanical device using the switch. , It may be necessary to stop the production line to repair the switch.

[Object of the Invention]

In view of such conventional problems, the present invention solves various drawbacks of a built-in switch, especially a snap-action switch, and also improves the setting of operators such as a switch operating plunger and a lever, and a movable part of the switch. The purpose is to know the recovery failure in advance.

[Outline of Invention]

In order to achieve the object, the present invention replaces the switch built in the housing with a snap-action switch, and uses an optical sensor, which is arranged along the moving direction of an actuator that optically opens and closes the optical sensor. Three sets of optical sensors are provided, and the operating positions of the two sets of optical sensors among the three sets of optical sensors are reduced as much as possible, and the operating output is obtained by the first operating optical sensor, and the optical sensor is restored first. The return output is obtained by the optical sensors, and the remaining one set of optical sensors is assembled with the other two sets of optical sensors while being offset by a certain amount, and the poor setting of the operator is predicted from the operating state of those three sets of optical sensors. Or to predict the restoration failure of the movable part by measuring the difference between the restoration times of the three optical sensors. Either one of the two sets of optical sensors fails. The output signal of the switch even if is ensured.

〔Example〕

An embodiment of the present invention will be described below with reference to the drawings.

That is, in FIG. 1 and FIG. 2, the housing 1
The head 3 is detachably attached to one end, that is, the head, on the axis of the. A rotary shaft 4 is arranged in this head so as to extend in a direction intersecting the axis of the housing 1. One end of the rotary shaft 4, that is, a portion protruding from the head 3, is connected with an operator 5, that is, one end of a lever, and a roller 6 is rotatably supported at a free end of the lever. A cam portion 7 having a flat surface is formed on a portion of the rotary shaft 4 located inside the head 3,
A cup plunger 8 is in contact with one surface of the cam portion by a spring 9. One end of the internal plunger 11 is in contact with the other surface of the cam portion 7, and the other end extends into the housing 1. This internal plunger converts the rotational movement of the operating element 5, that is, the rotary shaft 4, into a linear movement along the axis of the housing 1. A diaphragm seal 12 is provided between the housing 1 and the head 3 to control the seal therebetween, and an inner plunger 11 penetrates airtightly through a central portion of the seal. A built-in switch 13 is housed in the housing 1. This switch is the third
As shown in the figure, it has a case 14, and this case has an actuator.
15 are arranged along the axis thereof. This actuator is formed of a non-translucent material in the shape of an elongated plate, and has a first position along the axis of the case 14, that is, a free position before movement,
It is reciprocally supported between the second position, that is, the operating position after the movement. A plunger 17 is connected to one end of the actuator, and the plunger projects to the outside of the case 14. A cap-shaped seal member 18 is provided between the plunger and the case 14 to control the seal between them. Further, a spring 19 is provided between the other end of the operator 15 and the case 14, and the operator 15 is always urged to the first position, that is, the free position side by this spring.

Further, one end of the operating lever 21 is provided with a pin 22 in the housing 1.
Rotatably supported by its free end abutting the plunger 17 and its middle part an internal plunger 11.
Abut with the other end of. Thereby, the actuator 15 is interlocked with the movement of the operator 5.

In the case 14, three optical sensors 23, that is, 23a, 23b,
23c is accommodated. This optical sensor is composed of a light projecting element 25 and a light receiving element 26 which are optically opposed to each other, and a predetermined space is provided between both elements. The optical sensors 23a, 23b, and 23c maintain a predetermined distance in the moving direction of the actuator 15 so that the actuator 15 optically separates the light projecting element 25 and the light receiving element 26 from each other. It is arranged so that.

On the other hand, the actuator 15 selectively guides the light from the light projecting element 25 of each of the optical sensors 23a, 23b, and 23c to the light receiving element 26.
The individual light transmitting windows 27, 28, 29 are provided apart from each other in the moving direction thereof, that is, in the axial direction of the case 14. The translucent window and the optical sensors 23a, 23b, 23c are the actuator 1
The third optical sensor has a positional relationship such that the operation time point of the first optical sensor 23a and the operation start time point of the second optical sensor 23b when moving 5 are as small as possible, that is, substantially equal to each other. The operation start time of 23c is different from the operation disclosure time of the first and second optical sensors 23a and 23b. Therefore, the third optical sensor 23
The c is attached at a position displaced from the other optical sensors 23a and 23b by a certain amount.

In addition, the first optical sensor 23a and the second optical sensor 23b are to obtain the operation output of the switch. Of these two optical sensors, the one that operates first obtains the operation output, and the one that returns earlier returns the output. To get.

Furthermore, the third optical sensor 23c detects a diagnostic signal.

In FIG. 4, the case 14 is covered with a cover 32, and an electronic circuit board 30 forming an electronic circuit is attached to the cover 32.

 The opening of the housing is covered with the cover 31.

In the above structure, when the operator 5, that is, the lever rotates from the free state about the rotary shaft 4, the amount of rotation thereof is changed to the amount of direct change of the internal plunger 11, and the operator 15 is pressed through the lever. . When the actuator is in the free position, the light emitted from the light projecting elements 25 of the three sets of photosensors 23a, 23b, 23c is blocked by the actuator 15 as shown in FIG. Element 26 is not reached.

Next, when the actuator 15 reaches the position shown in FIG. 5B in the process of moving from the free position to the operating position against the spring 19, the first transparent window 27 causes the first transparent window 27 to move the first position. The light emitted from the light projecting element 25 of the optical sensor 23a reaches the light receiving element 26. Operation output from the first optical sensor 23a, as shown at time t ₁ of FIG. 6 at this time is issued.

Subsequently, when the operating element 5 reaches a sufficient movement amount, that is, a predetermined rotation amount, the operating element 15 reaches the position shown in FIG. 5C, and the second light transmitting window 28 is used to project the second optical sensor 23b. light emitted from the optical device 25 reaches its light-receiving element 26, the second optical sensor 23b, as shown at time t ₂ of FIG. 6 emits a signal. In this state, the first and second optical sensors 23a and 23b are operating.

Further, when the operator 5 enters overtravel, that is, the movement after the operation and reaches a sufficient rotation amount, the operator 15 moves to the fifth position.
In the state shown in FIG. 4D, the light emitted from the light projecting element 25 of the third optical sensor 23c through the third light transmitting window 29 is received by the light receiving element 2
Reaches the 6, the third optical sensor 23c, as shown at time t ₃ of FIG. 6 emits a signal. In this state, the first and second
The optical sensors 23a and 23b of are also operating.

At this time, if the overtravel is insufficient, that is, if the actuator 15 starts to return after the first and second optical sensors 23a and 23b operate and before the third optical sensor 23c operates, that is, in FIG. When the operator 15 starts to recover in the state shown, a failure prediction output is given as a failure to explain that the setting of the operator 5 is not correct, that is, the operator 15 has not sufficiently moved to the operating position. As shown in FIG. 6, this detection is performed by a timer counter (not shown) at time t _1, that is, at the time when the first optical sensor 23a operates, and starts counting from a timer counter (not shown) until the third count is reached. This is performed when the optical sensor 23c of does not operate.

Next, when the operating element 5 is in a sufficient operating position, that is, the operating element 15 is in the second position, the external force applied to the operating element 5 is removed, and the operating element is moved to its original position by the spring 9 and the cup plunger 8. Start returning to. At the same time, the actuator 15 is moved to the second position by the urging force of the spring 19 as shown in FIG.
From the first position, that is, the operating position, toward the first position, that is, the free position. Its actuator 15 as opposed to the by connexion prior to block light reaching the light receiving element 26 from the light projecting element 25 of the third optical sensor 23c at the time t ₄ of Figure 6. That is, the third optical sensor 23c returns to the state shown in FIG. At this point in time, a timer counter for poor recovery, not shown, starts counting.

When the actuator 15 continues the returning motion, the actuator 15 moves to the sixth position.
At time t ₅ in the figure, the light from the light projecting element 25 to the light receiving element 26 of the second photosensor 23b is blocked. That is, the second optical sensor 23
b returns to the state shown in FIG. At the same time, the output signal of the switch is turned off. At this time, the timer counter stops counting.

At this time, if the number of counts of the timer counter becomes equal to or more than the value set in advance, the switch outputs a failure prediction signal as a failure prediction signal. On the contrary, if the count number is smaller than the default value, the timer counter is initialized.

In this way, as the output signal of the switch, the operation output is obtained by the one that operates first and the return output by the one that returns first, of the two optical sensors 23a and 23b. the operation output at t _1, and because to obtain a return output at t ₄ in the figure, if the switch output to the outside even when either one of the optical sensor fails is ensured.

In addition, the setting failure of the manipulator 5 is the number of counts from the output time of the first operating optical sensor, and the three optical sensors 23a, 23a
This is performed by detecting the operating states of b and 23c.

Further, the defective restoration of movable parts such as the operating element 5, that is, the lever, the rotary shaft 4, the cup plunger 8, the internal plunger 11, the operating lever 21 or the operating element 5 is detected by the number of counts from the output time point of the optical sensor which has previously returned. To be done.

Further, when the operator 5 is completely returned to the original position and the actuator 15 is returned to the first position, that is, the free position, the sixth
Actuator 15 at time t ₆ in FIG intercepts light reaching to the light receiving element 26 from the light projecting element 25 of the first optical sensor 23a, to return it.

The control of the output signal of these switches and the failure prediction control can be performed by using a computer, for example, a microcomputer.

The above-mentioned optical sensor 23 is usually the second optical sensor 23b.
To operate first, the optical sensors 23a, 23b and the translucent windows 27, 28
It is possible to set a relative positional relationship with and the action in this case is substantially the same as the above-mentioned embodiment.

Further, although the roller lever type is shown as the manipulator 5, a lever can be used for a normal lever type, and an external plunger can be used for a plunger type.

The block diagram shown in FIG. 7 is for predicting a switch failure by using a well-known computer, and the CPU 34 is a normal CPU including an arithmetic unit, a control unit, a memory, and a timer counter.
Has all the functions of a CPU. And this CPU has a driver circuit 35, 35 for driving the light emitting elements 25, 25 and a light receiving element.
Light receiving circuits 36, 36 for converting the optical signals from 26, 26 into electric signals are connected, respectively. Further, the CPU 34 includes a fixing pressure circuit 37, a control output driver circuit 38, a control output display circuit 39, an output transistor diagnostic circuit 40, and a failure prediction output driver circuit 4
1, the failure prediction display circuit 42 and the like are connected, the control output display circuit 39 further has an indicator light 43, the failure prediction display circuit 42 has an indicator light 44, and the control output driver circuit 38 has a transistor 45. Further, the transistor 46 is connected to the failure prediction output driver circuit 41, respectively.

The power source 47 is connected between the terminal a and the ground G, the load 48 is connected between the terminals a and b, and the load 49 is connected between the terminals a and c.

〔The invention's effect〕

Since the present invention uses an optical contact, that is, an optical switching element instead of the mechanical contact as the internal switch as described above, it causes contact welding, breakage of the movable contact plate, dust, etc., like the snap action switch. There is no risk of contact failure due to adhesion to the contacts.

Further, according to the present invention, the three optical sensors and the three light-transmitting windows are made to substantially coincide with each other so that the deviation between the operation starting time of the first optical sensor and the operation starting time of the second optical sensor is as small as possible. And the third optical sensor is arranged in a positional relationship different from that of the first and second optical sensors, and the operation output is obtained by the first one of the first and second optical sensors that operates first, and Since the return output is obtained by the optical sensor that returns first, the switch output can be secured even if any of the optical sensors fails.

Furthermore, since the operator's setting error is detected by detecting the operating state of the three optical sensors, if the setting position shifts due to loosening of the screw etc. while using the switch, the switch output can be obtained. You can know before you can not.

Moreover, since the recovery time of the three optical sensors is measured to detect the recovery failure of the movable part,
The state can be known at the time when the movement of the movable portion starts to become slower than the set value, that is, before complete restoration failure occurs.

[Brief description of drawings]

FIG. 1 is a front view showing a switch according to the present invention with a cover removed, FIG. 2 is a side sectional view, FIG. 3 is an enlarged front view of a built-in switch, FIG. 4 is an exploded perspective view of the built-in switch, and FIG. Is a front view showing the operating state of the built-in switch, FIG. 6 is a waveform diagram showing the output state of the built-in switch, and FIG. 7 is a block circuit diagram. 1 ... Housing, 3 ... Head, 4 ... Rotation axis, 5 ...
… Operator, 6 …… Roller, 7 …… Cam part, 8 …… Cap plunger, 9 …… Spring, 11 …… Internal plunger, 12 …… Diaphragm seal, 13 …… Built-in switch, 14 …… Case, 15 …… Operator, 17 …… Plunger, 18 …… Seal member, 19 …… Spring, 21 …… Actuating lever, 22 …… Pin, 23 …… Optical sensor, 25 …… Emitting element, 26 …… Receiving light Element, 27 …… Transparent window, 28 …… Transparent window, 29
...... Transparent window, 30 ... Electronic circuit board, 31 ... Cover, 32 ...
… Cover, 34 …… CPU, 35 …… Driver circuit, 36 ……
Light receiving circuit, 37 ... Constant voltage circuit, 38 ... Control output driver circuit, 39 ... Control output display circuit, 40 ... Output transistor control circuit, 41 ... Failure prediction output driver circuit, 42
…… Fault prediction display circuit, 43 …… Indicator, 44 …… Indicator,
45 …… transistor, 46 …… transistor, 47 …… power supply, 48 …… load, 49 …… load.

Claims (3)

[Claims] 1. An operator (5) driven by an external force is supported so as to move relative to a housing (1), and is formed of a non-translucent material in the housing (1). In addition, the actuator (15) interlocking with the operator (5) is reciprocally supported between the first position and the second position, and the housing (1) has a predetermined interval therebetween. A light-emitting element (25) that is placed at a certain distance and is optically opposed
Optical sensor (23) composed of a light receiving element (26) and a light receiving element (26)
These three optical sensors are housed in the optical sensor so that the light emitting element and the light receiving element are optically separated by the actuating element (15) and in the moving direction of the actuating element (15). Three light-transmissive windows (27) (28), which are arranged at predetermined intervals, and which further selectively guide light from the respective light-projecting elements to the respective light-receiving elements in the actuator (15). (29) are provided apart from each other in the moving direction, and the translucent window and the sensor (23) are separated from each other by the second operation start point of the first optical sensor when the actuator (15) is moved. The actuator (15) has a positional relationship such that it is substantially equal to the operation start time of the optical sensor, and the operation start time of the third optical sensor is different from the operation start times of the first and second optical sensors. From the first position to the second
In the process of moving to the first position, an operation output is obtained by the previously operated optical sensor, and in the process of moving the actuator (15) from the second position to the first position, the first
Alternatively, in the process of moving the actuator (15) from the first position to the second position while obtaining the return output from the second optical sensor which returns first, A switch with a failure prediction function, which detects a defect in the operating position of the operating element (5) when the third optical sensor does not operate after the second optical sensor operates. 2. An operator (5) driven by an external force is supported so as to move relative to the housing (1), and is formed of a non-translucent material in the housing (1). In addition, the actuator (15) interlocking with the operator (5) is reciprocally supported between the first position and the second position, and the housing (1) has a predetermined interval therebetween. A light-emitting element (25) that is placed at a certain distance and is optically opposed
Optical sensor (23) composed of a light receiving element (26) and a light receiving element (26)
These three optical sensors are housed in the optical sensor so that the light emitting element and the light receiving element are optically separated by the actuating element (15) and in the moving direction of the actuating element (15). Three light-transmissive windows (27) (28), which are arranged at predetermined intervals, and which further selectively guide light from the respective light-projecting elements to the respective light-receiving elements in the actuator (15). (29) are provided so as to be spaced apart from each other in the moving direction, and the translucent window and the sensor (23) are arranged such that the operation start time of the first optical sensor is the second light when the actuator (15) is moved. Almost the same as when the sensor started
And, the operation start time of the third optical sensor has a positional relationship such that it differs from the operation start times of the first and second optical sensors, and the actuator (15) moves from the first position to the second position. In the process of moving to, the operation output is obtained by the previously operated optical sensor, and in the process of moving the actuator (15) from the second position to the first position, the first or second optical sensor is Among the above, the optical sensor returning first obtains a return output, and the third optical sensor and the first optical sensor when the actuator (15) returns from the second position to the first position. A switch with a failure prediction function, characterized in that a failure in restoration of a movable part is detected by measuring a restoration time difference between the sensor or the second optical sensor that has been restored first. 3. An operator (5) driven by an external force is supported so as to move relative to the housing (1), and is formed of a non-translucent material in the housing (1). In addition, the actuator (15) interlocking with the operator (5) is reciprocally supported between the first position and the second position, and the housing (1) has a predetermined interval therebetween. A light-emitting element (25) that is placed at a certain distance and is optically opposed
Optical sensor (23) composed of a light receiving element (26) and a light receiving element (26)
These three optical sensors are housed in the optical sensor so that the light emitting element and the light receiving element are optically separated by the actuating element (15) and in the moving direction of the actuating element (15). Three light-transmissive windows (27) (28), which are arranged at predetermined intervals, and which further selectively guide light from the respective light-projecting elements to the respective light-receiving elements in the actuator (15). (29) are provided so as to be spaced apart from each other in the moving direction, and these light-transmitting windows and the optical sensor (23) are separated from each other when the operation of the actuator (15) is started and when the operation of the first optical sensor is started. The actuator (15) has a positional relationship such that it is substantially equal to the operation start time of the optical sensor, and the operation start time of the third optical sensor is different from the operation start times of the first and second optical sensors. From the first position to the second
In the process of moving to the first position, an operation output is obtained by the previously operated optical sensor, and in the process of moving the actuator (15) from the second position to the first position, the first
Alternatively, in the process of moving the actuator (15) from the first position to the second position while obtaining the return output from the second optical sensor which returns first, When the third optical sensor does not operate after the second optical sensor operates, a defect in the operating position of the operating element (5) is detected, and the operating element (15) moves to the second position.
By measuring the return time difference between the third optical sensor and the first optical sensor or the second optical sensor that has returned first when returning from the position to the first position. A switch with a failure prediction function, which is characterized by detecting a return failure of a movable part.